α-Melanocyte-Stimulating Hormone Inhibits Allergic Airway Inflammation

Abstract

α-Melanocyte-stimulating hormone (α-MSH) is a neuropeptide controlling melanogenesis in pigmentary cells. In addition, its potent immunomodulatory and immunosuppressive activity has been recently described in cutaneous inflammatory disorders. Whether α-MSH is also produced in the lung and might play a role in the pathogenesis of inflammatory lung conditions, including allergic bronchial asthma, is unknown. Production and functional role of α-MSH were investigated in a murine model of allergic airway inflammation. α-MSH production was detected in bronchoalveolar lavage fluids. Although aerosol challenges stimulate α-MSH production in nonsensitized mice, this rapid and marked stimulation was absent in allergic animals. Treatment of allergic mice with α-MSH resulted in suppression of airway inflammation. These effects were mediated via IL-10 production, because IL-10 knockout mice were resistant to α-MSH treatment. This study provides evidence for a novel function of α-MSH linking neuroimmune functions in allergic airway inflammation.